1. Technical Field
The present invention relates to a cryopump and a method for vacuum pumping a non-condensable gas.
2. Description of the Related Art
A cryopump is a vacuum pump that captures and pumps gas molecules by condensing or adsorbing molecules on a cryopanel cooled to an extremely low temperature. A cryopump is generally used to achieve a clean vacuum environment required in a semiconductor circuit manufacturing process and the like. One of the applications of a cryopump includes a case where, for example, a non-condensable gas such as hydrogen makes up most of gas to be pumped, as in the case of, for example, an ion implantation step. The only way of pumping a non-condensable gas is to adsorb the non-condensable gas on an adsorption area that is cooled to an extremely-low temperature.